Morning journal and courier., 1887-10-06

From Fire and Water.l
 One of the most curious instances of spon- taneous ignition on record is that recently reported to the Iron Age by Chicago manu- facturer of plane bits. For some time 8 sponge had been used for wetting an emery wheel in his shop, bringing water up out of water-box by capillary attraction and touching the wheel It was kept against the wheel lightly by spring. The wheel was used in grinding very hard steel plates, therefore the sponge constantly wiped parti- cles of steel off the wheel during it's revolu- tions, and it was used in that way until these particles had filled up it's cells to very considerable degree. of course being wet all the time. It was then laid aside, the string being still attached to it together with lit- tie cotton cloth. In time it became entirely dry, lying on and against couple of pieces of fine wood. After lying unobserved for 8 week or ten days it was suddenly discovered one afternoon to be incandescent-in fact 8 living coal-and to have set fire both to the board on which it rested and the one against which it leaned. It had burned 8 considera- ble portion of the stout twine and the cotton cloth attached to it. All were smouldering, and although flames had not burst forth, they evidently would have done so in 8 short time. as the room contained very pungent smell of burning wood The boards were each burned to a depth of quarter of an inch and to a width approximately three inches when the incipient confagration was quenched. The appearance of the charred sponge was not much unlike that of a piece of roasted iron ore, which it differed from, however, very decidedly in weight, being quite light. When broken it exhibi- ted the same characteristics throughout, showing that the fine particles of steel had been thoroughly distributed in it's interior. This evident case of spontaneous ignition of an article which had not been saturated with grease or oil, but which consisted of piece of ordinary sponge, filled with fine particles of steel while it was in a wet state, naturally caused much discussion, but very plausible explanation of it's mysterious behavior has been made by the manufacturer himself as follows: The particles of steel which were wiped off the emery wheel by the sponge must necessarily have been exceedingly fine, as the steel was very hard, Lodging on the sponge in wet condition and in constant contact with water, oxidation was actlve-or in other words the particles rusted very rap idly. The fine particles of steel presented an extremely great surface area for such &C., tion as compared with their bulk. Under ordinary circumstances oxidation does not develop sensible heat, but under the peculiar conditions here realized the usually harm less chemical phenomenon of rusting devel- oped into an actual fire creating agent, and incandescence resulted. Here was an article which at first sight would seem to be as in- capable of spontaneous combustion as an or. dinary brick, but which proves to be entitled to rank with greasy rags and oily waste, and other we'll established fre-creating combina- tions Had not this burning mass been dis covered most auspiciously serious contia- grafton would in all probability have ensued. and it's cause would have been funknown."